Marijuana's boring sibling

Hemp and marijuana are fraternal twins: While they look similar, the plants are actually quite different. Agricultural hemp has only miniscule amounts of the psychoactive ingredient tetrahydrocannabinol (THC) that exists in marijuana; those trace levels are not enough to induce a chemical high.

Cultivated for over 10,000 years, hemp is grown legally in over 25 countries. Until relatively recently, it was also grown in the United States; during World War II the federal government subsidized hemp production.

However, federal drug law passed in 1970 has a zero-tolerance policy for THC and makes no distinction between hemp and marijuana, defining them both as Cannabis sativa. In fact, "hemp" is not a term that is found anywhere in federal drug law. "There is no way to break down the differences between the two plants," says Rogene Waite of the Drug Enforcement Agency.

In order for hemp to become legal, Congress will have to redefine the language of the law. There is currently no legislative effort to do this.